The GMC Sierra 3500HD, in its fifth generation (GMTT1XX), received a significant facelift for the 2024 model year. This iteration continues GMC’s tradition of offering a heavy-duty pickup truck geared towards demanding work and towing applications. The Regular Cab Long Bed configuration, paired with the 6.6-liter V8 gasoline engine producing 401 horsepower, represents a work-focused variant within the Sierra 3500HD lineup. Positioned as a robust, no-nonsense option, it caters to buyers prioritizing capability over luxury, though modern amenities are still included. Production began in late 2023 for the 2024 model year.
Technical Specifications
| Brand | GMC |
| Model | Sierra 3500HD |
| Generation | Sierra 3500HD V (GMTT1XX, facelift 2024) Regular Cab Long Bed |
| Type (Engine) | 6.6 V8 (401 Hp) SRW Automatic |
| Start of production | 2024 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 7.2 kg/Hp, 139.7 Hp/tonne |
| Weight-to-torque ratio | 4.6 kg/Nm, 219.2 Nm/tonne |
| Power | 401 Hp @ 5200 rpm |
| Torque | 629 Nm @ 4000 rpm (463.93 lb.-ft. @ 4000 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | L8T |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 103.25 mm (4.06 in) |
| Piston Stroke | 98 mm (3.86 in) |
| Compression ratio | 10.8:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Direct injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV |
| Engine oil capacity | 7.6 l (8.03 US qt | 6.69 UK qt) |
| Coolant | 14.6 l (15.43 US qt | 12.85 UK qt) |
| Kerb Weight | 2870 kg (6327.27 lbs) |
| Max. weight | 4966 kg (10948.16 lbs) |
| Max load | 2096 kg (4620.89 lbs) |
| Fuel tank capacity | 136 l (35.93 US gal | 29.92 UK gal) |
| Permitted trailer load with brakes (12%) | 6577 kg (14499.8 lbs) |
| Length | 6002 mm (236.3 in) |
| Width including mirrors | 2076 mm (81.73 in) |
| Height | 2056 mm (80.94 in) |
| Wheelbase | 3595 mm (141.54 in) |
| Front track | 1731 mm (68.15 in) |
| Rear (Back) track | 1736 mm (68.35 in) |
| Ride height (ground clearance) | 285 mm (11.22 in) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 10 gears, automatic transmission Allison |
| Front suspension | Independent torsion bar, double wishbone |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 355×40 mm |
| Rear brakes | Ventilated discs, 360×34 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Power steering | Hydraulic Steering |
| Tires size | 245/75 R17; 265/70 R17; 275/70 R18; 275/65 R20 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 20 |
Powertrain & Engine Architecture
The heart of this Sierra 3500HD variant is the 6.6-liter L8T V8 gasoline engine. This engine is a naturally aspirated, overhead valve (OHV) design, utilizing direct fuel injection for improved efficiency and power delivery. The L8T produces 401 horsepower at 5200 rpm and 464 lb-ft of torque at 4000 rpm. The engine’s robust construction is designed for high-load applications, making it well-suited for towing and hauling. The engine is mated to a heavy-duty 10-speed Allison automatic transmission, specifically calibrated for the demands of a heavy-duty truck. This transmission provides a wide gear ratio spread, optimizing both fuel economy and towing performance. The Allison transmission is known for its durability and smooth shifting characteristics.
Driving Characteristics
The 6.6L V8 and 10-speed automatic combination delivers a balance of power and usability. While not as quick as some of the diesel-powered Sierra 3500HD models, the gasoline engine provides ample power for everyday driving and demanding tasks. The 10-speed Allison transmission allows the engine to stay within its optimal power band, even when towing heavy loads. The gear ratios are tuned for both acceleration and fuel efficiency. Compared to the 6.6L Duramax diesel, this gasoline variant offers a more familiar driving experience for those accustomed to traditional gasoline engines, with a more linear power delivery. However, it lacks the diesel’s superior low-end torque and fuel economy when heavily loaded.
Equipment & Trim Levels
The Regular Cab Long Bed 6.6L V8 Sierra 3500HD typically comes standard with features geared towards work-truck functionality. This includes a basic infotainment system with a touchscreen display, Bluetooth connectivity, and a rearview camera. Interior upholstery is typically vinyl or cloth, designed for durability. Common standard features include air conditioning, power windows and locks, and a tilt-adjustable steering wheel. Optional extras often include upgraded infotainment systems with navigation, leather upholstery, heated and ventilated front seats, and a premium audio system. Work Truck and LT trims are the most common configurations for this powertrain.
Chassis & Braking
The Sierra 3500HD features a fully boxed frame designed for strength and rigidity. The front suspension utilizes an independent torsion bar and double wishbone setup, providing a comfortable ride even when the truck is unloaded. The rear suspension employs a traditional leaf spring design, optimized for load-carrying capacity. Braking duties are handled by ventilated disc brakes at all four corners, with the front discs measuring 355x40mm and the rear discs measuring 360x34mm. An Anti-lock Braking System (ABS) is standard. Steering is accomplished via a hydraulic power steering system with a cone worm and recirculation balls mechanism.
Market Reception & Comparison
The 6.6L V8 Sierra 3500HD received generally positive reviews for its capability and value. Critics noted that it offered a compelling alternative to diesel-powered trucks for buyers who didn’t require the diesel’s maximum towing capacity or fuel economy. Compared to the diesel variants, the gasoline engine is typically less expensive to purchase and maintain, although it does consume more fuel under heavy load. The gasoline engine also offers a quieter and smoother driving experience than the diesel. Fuel economy is rated at approximately 15 mpg city and 19 mpg highway, depending on driving conditions and load.
Legacy
The L8T 6.6L V8, paired with the Allison 10-speed automatic, has proven to be a reliable powertrain combination. While not as widely discussed as the Duramax diesel, it has earned a reputation for durability and relatively low maintenance costs. In the used car market, these trucks are often sought after by buyers looking for a capable and affordable heavy-duty pickup. The simplicity of the gasoline engine, compared to the more complex diesel, can make it a more attractive option for those who prefer to perform their own maintenance. As of 2024, the 2024 facelifted model continues to build on this legacy, offering a modern and capable work truck for a variety of applications.
